5Z8I

Solution structure of the SBDbeta domain of yeast Ssa1

Summary for 5Z8I

• Entry DOI: 10.2210/pdb5z8i/pdb
• NMR Information: BMRB: 36161
• Descriptor: Heat shock protein SSA1 (1 entity in total)
• Functional Keywords: hsp70, sbdbeta, chaperone
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
• Total number of polymer chains: 1
• Total formula weight: 18774.19

Authors

Gong, W.,Hu, W.,Wu, H.,Perrett, S. (deposition date: 2018-01-31, release date: 2018-09-26, Last modification date: 2024-05-15)

Primary citation

Gong, W.,Hu, W.,Xu, L.,Wu, H.,Wu, S.,Zhang, H.,Wang, J.,Jones, G.W.,Perrett, S.
The C-terminal GGAP motif of Hsp70 mediates substrate recognition and stress response in yeast.
J. Biol. Chem., 293:17663-17675, 2018

PubMed Abstract: The allosteric coupling of the highly conserved nucleotide- and substrate-binding domains of Hsp70 has been studied intensively. In contrast, the role of the disordered, highly variable C-terminal region of Hsp70 remains unclear. In many eukaryotic Hsp70s, the extreme C-terminal EEVD motif binds to the tetratricopeptide-repeat domains of Hsp70 co-chaperones. Here, we discovered that the TVEEVD sequence of cytoplasmic Hsp70 (Ssa1) functions as a SUMO-interacting motif. A second C-terminal motif of ∼15 amino acids between the α-helical lid and the extreme C terminus, previously identified in bacterial and eukaryotic organellar Hsp70s, is known to enhance chaperone function by transiently interacting with folding clients. Using structural analysis, interaction studies, fibril formation assays, and functional assays, we investigated the individual contributions of the α-helical bundle and the C-terminal disordered region of Ssa1 in the inhibition of fibril formation of the prion protein Ure2. Our results revealed that although the α-helical bundle of the Ssa1 substrate-binding domain (SBDα) does not directly bind to Ure2, the SBDα enhances the ability of Hsp70 to inhibit fibril formation. We found that a 20-residue C-terminal motif in Ssa1, containing GGAP and GGAP-like tetrapeptide repeats, can directly bind to Ure2, the Hsp40 co-chaperone Ydj1, and α-synuclein, but not to the SUMO-like protein SMT3 or BSA. Deletion or substitution of the Ssa1 GGAP motif impaired yeast cell tolerance to temperature and cell-wall damage stress. This study highlights that the C-terminal GGAP motif of Hsp70 is important for substrate recognition and mediation of the heat shock response.

PubMed: 30228181
DOI: 10.1074/jbc.RA118.002691

Experimental method

SOLUTION NMR